1. Field of the Invention
The present invention relates to an access point that communicates with a communication apparatus.
2. Description of the Related Art
In wireless communications such as a wireless local area network (LAN) conforming to Institute of Electrical and Electronic Engineers (IEEE) 802.11 series, a power saving mode is defined as a mode that suppresses power consumption in a communication apparatus.
As one of method of achieving a power-saving communication mode, saving the power of an access point (base station) has been discussed. For example, Japanese Patent Application Laid-Open No. 2004-336401 discusses a system in which an access point notifies, in advance, its terminal apparatus of a period of time when no data is transmitted/received. During the period, the access point operates in a sleep mode in which the wireless communication unit of the access point stops its function to save power of the access point.
In the power-saving communication mode, the access point in the sleep mode cannot transfer/receive messages to/from its terminal apparatus. As a result, when the terminal apparatus disengages from the network where the access point and the terminal apparatus belong, the access point cannot immediately detect the disengagement because the access point in the sleep mode cannot receive the disengagement message from the terminal apparatus.
Due to the above inconvenience, especially when the access point is a mobile device such as a laptop or a smartphone, the user of the device cannot have precise information about the state of a terminal apparatus that is a communication partner of the device, which is not user friendly.